Potential of green-based microporous carbon for advanced water decontamination from azo dyes: Experiment and molecular dynamic simulation studies

Abstract

Due to severe limitations in clean water resources, there has been an intensified focus on developing cost-effective, remarkably efficient, and recyclable adsorbents to enhance water quality. In this work, a cost-effective biobased activated carbon (AC) adsorbent was synthesized from date palm bark wastes and applied for the removal of two azo dye pollutants sunset yellow (SY), and tartrazine (TZ) from wastewater. The as-prepared powder of activated carbon was fully characterized using different analytical techniques including XRD, FTIR, XPS, Raman spectroscopy, zeta potential, FESEM, pHPZC and N2 adsorption-desorption analysis. These analyses revealed that the resulting biobased AC exhibited a graphene-like layered structure with a noticeable degree of structural order, decorated with diverse surface functional groups. The highly porous structure also demonstrated significant adsorption capacity for SY, and TZ contaminants, particularly at ambient temperatures. It achieved maximum uptakes of approximately 90 mg/g, and 65 mg/g for SY, and TZ respectively, spanning a wide pH range. Moreover, in-depth studies of the adsorption process, including kinetic and thermodynamic analyses, unveiled a chemical, spontaneous, and endothermic sorption mechanism for both SY, and TZ dyes, following a pseudo-second-order model adsorption behavior on the AC structure. Finally, an accurate adsorption mechanism has been proposed for the adsorption of dyes confirmed by experiments and molecular dynamic simulations.